Bag welding method and assembly for a bag filling station

ABSTRACT

A bag welding method and assembly includes an upper jaw movable in a substantially vertical plane and a lower jaw movable in the same substantially vertical plane as the upper jaw and supported on the frame via two support members. A pressure sensor is coupled to the jaws for measuring a welding pressure between the jaws. A processor coupled to the pressure sensor receives a signal from the pressure sensor to determine the conditions under which the weld was created. Preferably, the pressure sensor is mounted on one of the support members, or alternatively, can be mounted in a recess in one of the upper and the lower jaws. The welding assembly also preferably includes a temperature sensor for measuring the temperature between the welding jaws during sealing. The welding assembly can also include a timer for determining the length of time in which the welding jaws seal the bag.

FIELD OF THE INVENTION

[0001] The invention relates to devices for opening, filling, andsealing plastic bags and other packaging. More particularly, theinvention relates to automated devices that can produce an air-tightseal when packaging bulky products.

BACKGROUND OF THE INVENTION

[0002] Bag opening and filling devices have been developed for a widevariety of applications. Typically, these devices include one or moremechanisms for selecting a single bag from a stack of flattened, usuallyfolded bags, and holding the selected bag open for filling. Prior-artdevices commonly include a wicket that holds a stack of bags to befilled. Bags are torn from the wicket and opened prior to filling. Oncethe bag is opened, a pusher mechanism loads the product into the bag anda sealing mechanism seals the bag after the product has been loaded.

[0003] In modern packaging applications many different types of productsare loaded into bags. It is difficult to obtain an air-tight or hermeticseal using available automated sealing equipment when packaging bulkyproducts, such as diapers, sanitary napkins, paper napkins, and similarproducts. Fortunately, it is unnecessary to package these types ofproducts in air-tight bags. However, there are applications that requirehermetic sealing of the bag.

[0004] Packaging medical supplies is one such application. Hermeticsealing is required to ensure that the medical supplies are notcontaminated after they are packaged and sealed in the bags. Attempts toautomate the packaging and sealing of bulky medical supplies have beenunsuccessful due to the problems associated with placing a bulky objectin a flat bag and then attempting to bring the open edges of the bagtogether for sealing. The open edges wrinkle, which prevents theformation of a proper seal along the entire length of the bag opening.Consequently, bulky medical supplies are packaged and sealed by hand toensure that a hermetic seal is produced. Manual packaging and sealinghas several deficiencies. It is cumbersome, time-consuming, andvulnerable to human error.

SUMMARY OF THE INVENTION

[0005] Thus, there is a need for an automated packaging device that canbe used to package medical supplies and other products in bags and tohermetically seal the bags. In addition, it would be beneficial if sucha machine could monitor the quality of the seal. Further still, there isa need for a device where a relatively large number of bags can beloaded or otherwise provided to the packaging device so that product canbe packaged at a relatively high rate without the need for replenishingthe supply of bags at a similarly high rate.

[0006] In one embodiment, the invention provides an automated bagfilling station or packaging device capable of rapidly packaging medicalsupplies and other bulky products in bags and sealing the bags in anair-tight manner. The packaging device includes a welding assembly for abag filling device. The welding assembly includes an upper jaw movablein a substantially vertical plane and a lower jaw movable in the samesubstantially vertical plane as the upper jaw and supported on the framevia two support members. The welding assembly also includes a pressuresensor coupled to the jaws for measuring a welding pressure between thejaws. A processor coupled to the pressure sensor receives a signal fromthe pressure sensor to determine the conditions under which the weld wascreated.

[0007] In one aspect of the invention, the pressure sensor is mounted onone of the support members. In another aspect of the invention, thepressure sensor is mounted in a recess in one of the upper and the lowerjaws.

[0008] In yet another aspect of the invention, the welding assemblyincludes a temperature sensor for measuring the temperature between thewelding jaws during sealing. The welding assembly also includes a timerfor determining the length of time in which the welding jaws seal thebag.

[0009] In another embodiment, the invention provides a method of sealinga bag. The method includes positioning a bag between upper and lowerjaws and moving the jaws together in a substantially vertical plane toseal the bag. The method further includes sensing a pressure between thejaws when the jaws are together and sending pressure measurements to aprocessor. The processor then determines the quality of the seal byanalyzing whether the pressure measurements fall within a predeterminedset of allowable limits.

[0010] In one aspect of the invention, sensing the pressure includespositioning a pressure sensor on a support member coupled to one of theupper and the lower jaws. Additionally, a second pressure sensor can bepositioned on a second support member. Preferably, the support membersare substantially vertical when the jaws are together to obtain accuratepressure measurements. In another aspect of the invention, sensing thepressure between the jaws includes positioning a pressure sensor in arecess in one of the upper and the lower jaws.

[0011] In yet another aspect of the invention, the method furtherincludes sensing a temperature between the jaws when the jaws aretogether and sending temperature measurements to the processor todetermine the quality of the seal by analyzing whether the temperaturemeasurements fall within a predetermined set of allowable limits.

[0012] Other features and advantages of the invention will becomeapparent to those skilled in the art upon review of the followingdetailed description, claims, and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a side view of an automated packaging device embodyingthe invention.

[0014]FIGS. 1a and 1 b are top views of the package loading assembly invarious operating states.

[0015]FIG. 2 is an enlarged side view showing one of the support membersof FIG. 1 in the package sealing position.

[0016]FIG. 3 is an enlarged side view showing the bag loading assemblyof the device of FIG. 1.

[0017] FIGS. 4-6 are side views of the conveyor assembly portion of thebag loading assembly of FIG. 3 shown in various operational states.

[0018]FIG. 7 is a partially cut away view of the conveyor assembly takenalong line 7-7 in FIG. 4.

[0019]FIG. 8 is a front view showing a loading station, a bagmanipulating assembly, and a bag welding assembly of the device of FIG.1.

[0020]FIG. 9 is an enlarged front view of the loading station and thebag manipulating assembly shown with a bag opened for receiving apackage.

[0021]FIG. 10 is a perspective view of the loading station, the bagmanipulating assembly, and a portion of a bag loading assembly loading apackage into the opened bag.

[0022]FIG. 11 is an alternative gripper arrangement that can be usedwith the bag manipulating assembly.

[0023]FIG. 12 is a sectional view of the welding jaws showing analternative pressure sensor configuration.

[0024] FIGS. 13-20 sequentially illustrate, in cross-section from theside, the opening, closing, and sealing of the bag.

[0025] FIGS. 21-28 sequentially illustrate, from the front, the opening,closing, and sealing of the bag.

[0026]FIG. 29 is a sealed bag containing a package.

[0027] FIGS. 30-32 illustrate an alternative spreader plate arrangementfor the bag manipulating assembly.

[0028] Before the invention is explained in detail, it is to beunderstood that the invention is not limited in its application to thedetails of construction and the arrangements of the components set forthin the following description or illustrated in the drawings. Theinvention is capable of multiple embodiments and of being practiced orbeing carried out in various ways. Also, it is understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The useof“including” and “comprising” and variations thereof herein is meant toencompass the items listed thereafter and equivalents thereof as well asadditional items.

DETAILED DESCRIPTION

[0029] A bag filling station 50 of one embodiment is shown in FIG. 1.The bag filling station 50 includes a frame 54 (only partially shown)that supports the bag filling station 50. The frame 54 can also supportprotective walls (not shown) positioned around the bag filling station50, as is commonly understood.

[0030] The bag filling station 50 includes a loading station 58positioned within the frame 54, a package loading assembly 62 coupled tothe frame 54 adjacent the loading station 58, a bag loading assembly 66coupled to the frame 54 adjacent the loading station 58, a bagmanipulating assembly 70 coupled to the frame 54 adjacent the loadingstation 58, and a bag welding assembly 74 (see FIG. 8) coupled to theframe 54 adjacent the loading station 58. For purposes of descriptiononly, the bag filling station 50 can be defined in terms of a front 78,adjacent the package loading assembly 62, a rear 82 adjacent the bagloading assembly 66, a right side 86, and a left side 90 (see FIG. 8). Alongitudinal axis 94 (see FIGS. 1, 1a, 1 b, 9, and 10) extends from thefront 78 to the rear 82 through the loading station 58.

[0031] As seen in FIGS. 1, 1a, 1 b, and 10, the package loading assembly62 includes a package conveyor assembly 98 capable of transportingpackages 102 to the loading station 58. The package conveyor assembly 98includes a conveyor table 106 supported by support legs 110 (see FIG.1). The conveyor table 106 includes an endless conveyor belt 114 (seeFIG. 10) driven by a drive device 118 (see FIG. 1). A suitable conveyortable 106 is available from Dorner Manufacturing of Hartland, Wis. Thedrive device 118 can be any suitable device capable of moving theconveyor belt 114, such as an electric motor.

[0032] The package conveyor assembly 98 also includes a pair of pusherarm assemblies 122 movably coupled to the conveyor table 106. The pusherarm assemblies 122 are substantially identical, and only one will bedescribed. As seen in FIG. 1, the pusher arm assembly 122 includes aslide 126 mounted on a support member 130 for reciprocating linearmovement in the direction of the longitudinal axis 94. The linearmovement of the pusher arm assembly 122 is driven by any linear actuator(not shown) such as a hydraulic or pneumatic actuator, a rack and pinionsystem, and the like, or can be driven by the drive device 118.

[0033] The pusher arm assembly 122 also includes a pusher arm 134 havinga pushing end 138 for pushing a package 102 into the loading station 58.As best seen in FIG. 1a, the pusher arm 134 is movable between aretracted position P_(R) (shown in solid lines in FIG. 1a), where apackage 102 can be advanced on the conveyor table 106 between the twopusher arms 134 toward the loading station 58, and an extended positionP_(E) (shown in phantom lines in FIG. 1a), where the two pusher arms 134overlie the conveyor table 106. As shown in FIG. 1b, when in theextended position, the pusher arms move linearly from the position P₁(shown in solid lines in FIG. 1b), to the position P₂ (shown in phantomlines in FIG. 1b) so that the pushing ends 138 can push the package 102into the loading station 58.

[0034] Any suitable method of causing the movement of the pusher arms134 between the retracted and extended positions can be used, includinghydraulic or pneumatic actuators, rack and pinion systems, and the like.While the package conveyor assembly 98 preferably includes two pusherarm assemblies 122, it is understood that only one pusher arm assembly122 could be used. Pusher arm assemblies having other configurations arealso contemplated, including those shown in U.S. Pat. No. 5,799,465incorporated by reference herein.

[0035] The package conveyor assembly 98 also preferably includes asensor 142 (see FIG. 1) that senses the presence of a package 102 on theconveyor table 106 when the package 102 is adjacent the loading station58. The sensor 142, which can be in the form of an optical sensor, alimit switch, or the like, communicates with the pusher arm assemblies122 so that the pusher arm assemblies 122 are activated to push thepackage 102 when the package 102 is in position adjacent the loadingstation 58.

[0036] The package conveyor assembly 98 can also include guide rails 144(see FIGS. 1a and 1 b) on either side of the conveyor table 106extending substantially parallel to the longitudinal axis 94 to helpguide the package 102. The guide rails 144 can be adjustable toaccommodate packages 102 of varying heights and widths.

[0037] As seen in FIGS. 1 and 3-7, the bag loading assembly 66 includesa bag feeder or bag conveyor assembly 146 capable of transporting a bag150 to the loading station 58 for receiving a package 102. The bags havean open end for receiving the package 102. The bag conveyor assembly 146includes a conveyor assembly 154 supported by support legs 158. As bestseen in FIGS. 3-7, the conveyor assembly 154 includes a conveyor table160 comprised of a body portion 162, a drive roller 166, a followerroller 170, a pair of tensioner rollers 174, an endless conveyor belt178 encircling portions of the body portion 162 and the rollers 166,170, and 174, and side supports 180 (only one is shown in FIG. 3).

[0038] The body portion 162 includes an upper cavity 182 and a lowercavity 186 separated by a wall 190. The wall 190 separates the cavities182, 186 such that there is substantially no fluid communication betweenthe cavities 182, 186. Upper and lower inlet ports 194 and 198,respectively (see FIG. 3), provide fluid communication to the cavities182, 186 as will be described below. The body portion 162 furtherincludes a top surface 202 having elongated apertures 206 communicatingbetween the top surface 202 and the upper cavity 182. The body portion162 also includes a bottom surface 210 having elongated apertures 214that are substantially identical to the apertures 206 and thatcommunicate between the bottom surface 210 and the lower cavity 186. Thebody portion 162 has an overall width W (see FIG. 7).

[0039] Vacuum from a vacuum generator 218 (see FIG. 1) is applied to thebody portion 162 through separate supply hoses 222 and 223. The uppersupply hose 222 provides vacuum to the upper cavity 182 through theupper inlet port 194. The lower supply hose 223 provides vacuum to thelower cavity 186 through the lower inlet port 198. Of course, twoseparate vacuum generators could be used.

[0040] The elongated apertures 206, 214 supply vacuum to the respectivetop and bottom surfaces 202, 210 over a working width W′ (see FIG. 7).The working width W′ of vacuum at the top and bottom surfaces 202, 210is adjustable to accommodate the width of the bags 150 being used. Inone embodiment, as shown in FIG. 7, a working width adjustment mechanism226 is used to selectively block and unblock all or portions of some ofthe apertures 206, 214. To accomplish this, a pair of slide plates 230(only the top slide plate is shown in FIG. 7) is moved to block andunblock the apertures, 206, 214. The slide plates 230 can be actuatedmanually or automatically.

[0041] The drive roller 166 is spaced from one end of the body portion162, preferably in the rearward direction, and is supported for rotationbetween the side supports 180. A drive device 234 drives the driveroller 166. In one embodiment, the drive device 234 is an electricmotor, and more preferably an electric motor that is programmed toactuate the drive roller 166 through a predetermined number ofrevolutions in either direction as will be described below.Alternatively, a standard electric motor could be used in conjunctionwith a sensing device (not shown) such as an optical sensor, a limitswitch, or the like.

[0042] The follower roller 170 is spaced from the end of the bodyportion 162 opposite the drive roller 166, and is also supported forrotation between the side supports 180. The follower roller 170preferably includes a cavity 238 that communicates with apertures 242formed in the surface of the follower roller 170. A vacuum is applied tothe follower roller 170 as shown schematically in FIG. 7. The vacuumgenerator 218 or a separate vacuum generator (not shown) is used tosupply vacuum to the follower roller 170. It should be understood,however, that the follower roller 170 need not be configured to providevacuum.

[0043] The endless conveyor belt 178 encircles the rollers 166, 170 suchthat there is always a portion of the conveyor belt 178 engaging boththe top surface 202 and the bottom surface 210. The tensioner rollers174 are supported for rotation between the side supports 180 as shown inFIG. 3, and at least one of the tensioner rollers 174 is movable toadjust the tension in the conveyor belt 178 as is understood. Of courseother arrangements can be used to adjust the tension of the conveyorbelt 178.

[0044] As seen in FIG. 7, the conveyor belt 178 includes a plurality oftransverse apertures 246 that provide communication between the outersurface of the conveyor belt 178 and the respective top and bottomsurfaces 202, 210 so that the vacuum supplied from the vacuum generator218 to the body portion 162 can communicate with the outer surface ofthe conveyor belt 178. In the illustrated embodiment, each transverseaperture 246 communicates with two apertures 206 when adjacent the topsurface 202 and two apertures 214 when adjacent the bottom surface 210.The transverse apertures 246 also communicate with the apertures 242 inthe follower roller 170 so that a vacuum is also applied to the outersurface of the conveyor belt 178 as the conveyor belt 178 passes overthe follower roller 170.

[0045] Although it is preferable to use vacuum, the conveyor table 160need not be configured to supply vacuum to the conveyor belt 178.Rather, the conveyor table 160 could use other suitable techniques, suchas static attraction, to engage and manipulate the bags 150 in themanner discussed below.

[0046] The conveyor table 160 is pivotable about the axis of rotation ofthe drive roller 166 between a first, substantially horizontal positionP_(H) (as shown in solid lines in FIGS. 1 and 3), and a second, inclinedposition P_(I) (as shown in phantom lines in FIGS. 1 and 3). The purposeof this movement will be described below. A drive device 250 (seeFIG. 1) is connected via linkage members 254 to one or both of the sidesupports 180 adjacent the follower roller 170 as shown. Activation ofthe drive device 250 moves the linkage members 254 to move the conveyortable 160 between the first and second positions P_(H), P_(I). Ofcourse, other methods of moving the conveyor table 160 between the firstand second positions, such as the use of actuators, rack and pinionsystems, and the like, are also contemplated.

[0047] As best seen in FIGS. 1 and 3, the bag conveyor assembly 146 alsoincludes a bag holder or cartridge tray assembly 258 underneath theconveyor table 160 for holding a stack of bags 150. A bag tray 262 issupported by the support legs 158 and receives a stack of bags 150 whichare positioned between guide walls 266 (only two are shown in FIGS. 1and 3). To facilitate replacing the stack of bags 150 in the bag tray262, the bag tray 262 is preferably mounted on rollers 270 (see FIG. 3)and can be rolled out from underneath the conveyor table 160.

[0048] As best seen in FIG. 3, a lifting plate 274 inside the bag tray262 is connected to a lifting mechanism 278 that is fixed to one of thesupport legs 158. The lifting mechanism can be an actuator, a rack andpinion system, or the like. As will be described below, the liftingmechanism 278 is actuated to move the lifting plate 274 to raise orlower the stack of bags 150 with respect to the bottom of the bag tray262.

[0049] The conveyor assembly 154 can also include a take-off conveyor282 (see FIGS. 3-7) for receiving filled bags 150 as they exit theconveyor table 160. The take-off conveyor 282 acts as a bridge betweenthe conveyor table 160 and a permanent conveyor (not shown) thattransports the filled bags 150 to an off-loading point. Of course, thetake-off conveyor 282 can be eliminated if the permanent conveyor isarranged adjacent the drive roller 166 of the conveyor table 160.

[0050] The loading station 58 is positioned between the package loadingassembly 62 and the bag loading assembly 66 and is best seen in FIGS. 1and 8-10. The frame 54 includes a substantially rectangular supportsection 286 (see FIGS. 1 and 8) which substantially surrounds theloading station 58 and which supports the bag manipulating assembly 70and the bag welding assembly 74. Upper and lower transverse shafts 290and 294, respectively, are supported for rotation by the support section286 and are coupled together via linkages 298. A drive device 302 (seeFIG. 8) is coupled to the lower shaft 294 and selectively rotates thelower shaft 294 in either direction. When the lower shaft 294 isrotated, the linkages 298 cause rotation of the upper shaft 290.

[0051] A pair of upper support members or struts 306 are mounted to theupper shaft 290 and connect the upper shaft 290 to an upper jaw supportmember 310 (see FIG. 8). The upper jaw support member 310 is movablysupported on substantially vertical guide rails 314 within the framesupport section 286. Rotation of the upper shaft 290 causes verticalmovement of the upperjaw support member 310, as will be described below.

[0052] Likewise, a pair of lower support members or struts 318 aremounted on the lower shaft 294 and connect the lower shaft 294 to alower jaw support member 322. The lower jaw support member 322 ismovably supported on the guide rails 314. Rotation of the lower shaft294 causes vertical movement of the lower jaw support member 322, aswill be described below. Each of the lower struts 318 has mountedthereon a pressure measurement device or sensor 324. The pressure sensor324 is preferably a load cell. For reasons to be explained in moredetail below, the lower struts 318 are sized so that as the lower jawsupport member 322 reaches its uppermost vertical limit, the struts 318are oriented substantially vertically as shown in FIG. 2. If the rangeof motion of the lower jaw support member 322 is varied for differentapplications, the struts 318 can be adjusted so that the struts 318 willalways be substantially vertical when the lower jaw support member 322reaches the uppermost vertical limit.

[0053] The upper and lower jaw support members 310, 322 support portionsof the bag manipulating assembly 70 and the bag welding assembly 74. Asbest seen in FIG. 9, the lower jaw support member 322 supports a lowerwelding jaw 326, which will be described in more detail below. Aplurality of suction cup assemblies 330 are mounted in spaced relationon a front face of the lower welding jaw 326. Each suction cup assembly330 is connected to a vacuum supply and can selectively apply suctionvia a suction cup 334. As will be described below, the suction cupassemblies 330 are used to engage an open end of the bag 150.

[0054] A pair of rotary actuators 338 are also mounted on the lower jawsupport member 322. Each rotary actuator includes a pin 342 that can beboth rotated and translated with respect to the housing of the rotaryactuator 338, as is understood. A spreader plate 346 is mounted on thepin 342 of each rotary actuator 338. The purpose of the spreader plate346 will be described below. Together, the suction cup assemblies 330,the rotary actuators 338, and the spreader plates 346 define a lower bagspreader assembly 348.

[0055] The upper jaw support member 310 supports an upper welding jaw350 and a substantially identical upper bag spreader assembly 352 inopposing relation to the lower bag spreader assembly 348. The upper bagspreader assembly 352 includes suction cup assemblies 354 having suctioncups 358, and a pair of rotary actuators 362. Each rotary actuator 362has a pin 366 and a spreader plate 370 mounted on the pin 366.

[0056] Additionally, the upper jaw support member 310 includes a pair ofcam members 374 adjustably mounted to mounting plates 378. The cammembers 374 are substantially identical and only one will be described.Each cam member 374 is fastened to one mounting plate 378 via upper andlower fasteners 382 and 383. The upper fastener 382 is received in aslot 386 in the cam member 374 such that the cam member 374 is pivotallyadjustable about the lower fastener 383. The cam member 374 furtherincludes a cam surface 390 corresponding to an edge of the cam member374. Adjustment of the cam member 374 changes the angle of the camsurface 390. The cam surface 390 can include an optional dwell point 394(shown in phantom in FIG. 9), which will be described below.

[0057] The cam members 374 cooperate with another portion of the bagmanipulating assembly 70. As best seen in FIGS. 8 and 9, a support beam398 is fixedly supported between the guide rails 314. Unlike the upperand lower jaw support members 310, 322, the support beam 398 is not freeto move vertically along the guide rails 314. A pair of gripper armassemblies 402 (see FIG. 9) are mounted on the support beam 398 inspaced-apart, opposing relation. The gripper arm assemblies 402 aresubstantially identical, and only one will be described in detail.

[0058] Each gripper arm assembly 402 includes a bracket member 406having a base portion 410 and an arm portion 414. A gripper arm 418 ispivotally connected to the base portion 410 at pivot point 422. A camfollower 426 is mounted to the gripper arm 418 and engages the camsurface 390. In the illustrated embodiment, the cam follower 426 is aroller. A linear actuator or gripper 430 is mounted on the end of thegripper arm 418 for gripping the side edges of a bag 150, as will bedescribed below. The gripper 430 is preferably a pneumatically-actuated,parallel gripper.

[0059] With continuing reference to FIG. 9, as the upper jaw supportmember 310 moves downwardly, the cam followers 426 roll on the camsurfaces 390 and the gripper arms 418 pivot about the pivot points 422in a plane substantially normal to the longitudinal axis 94. Downwardmovement of the upper jaw support member 310 causes the gripper arms 418and the grippers 430, to move away from one another. As the upper jawsupport member 310 moves upwardly, the gripper arms 418 and the grippers430 move back toward each other in a plane substantially normal to thelongitudinal axis 94. The dwell points 394 in the cam surfaces 390 aredesigned to change the cam surfaces 390 so that the pivot arms 418 willnot pivot during certain points of the operation of the bag fillingstation 50, as will be described below.

[0060] On both gripper arm assemblies 402, a linear actuator 434 isconnected between the arm portion 414 and the gripper arm 418. Together,the linear actuators 434 are operable to pivot the gripper arms 418 evenfurther away from one another than would otherwise occur via the normalmovement of the cam followers 426 along the cam surfaces 390. The linearactuators 434 are preferably short-stroke pneumatic actuators. As willbe described below, the linear actuators 434 are preferably actuatedjust prior to the sealing of the bag 150 when the upper jaw supportmember 310 is at its lowermost vertical limit.

[0061]FIG. 11 illustrates a pair of alternative gripper assemblies 438that can be used in place of the gripper arm assemblies 402. Instead ofthe cam action used to pivot the gripper arm assemblies 402, thealternative gripper assemblies 438 are fixedly mounted to the opposingvertical members of the frame support section 286, and are linearlyactuated to move the grippers 430 toward or away from each other. Thegripper assemblies 438 are substantially identical and includeback-to-back cylinders 442, 443 having respective rods 446, 447.

[0062] The rod 446 is connected to a sliding portion 450 which slides ona guide rail 454. Actuation of the cylinder 442 moves the rod 446 andcauses movement of the sliding portion 450. The rod 447 is connected toa body portion 456 that is fixed with respect to the frame supportsection 286. Actuation of the cylinder 443 causes the cylinders 442 and443 to move with respect to the body portion 456, thereby causingmovement of the sliding portion 450. The gripper 430 is mounted on thesliding portion 450 so that actuation of either of the cylinders 442,443 causes the grippers 430 to move toward or away from one another.

[0063] The components of the bag manipulating assembly 70 operate toreceive the bag 150 from the bag loading assembly 66, open the open endof a bag 150 so that the package 102 can be inserted, and close the openend of the bag 150 once the package 102 has been inserted. The bag 150is closed in a manner that is conducive to obtaining a quality seal ofthe open end of the bag 150. The bag 150 is under the control of the bagmanipulating assembly 70 from the time it is received to the time it isremoved from the loading station 58.

[0064] The bag welding assembly 74 is used to weld or seal the open endof the bag 150 after the package 102 has been inserted. The weldingassembly 74 includes the upper and lower welding jaws 350, 326 and theassociated hardware which are available from TOSS Machine ComponentsInc. of Nazareth, Pa. As seen in FIG. 13, in one embodiment, each of thewelding jaws 326, 350 includes a body portion 458, a fiberglass strip462, a silicon strip 466, a teflon strip 470, and a weld wire 474. Alayer of teflon tape 478 surrounds the working ends of the welding jaws326, 350. Of course, welding could be accomplished with only one of thewelding jaws 326, 350 having a weld wire 474.

[0065] The upper welding jaw 350 can also include a cutter assembly 482that trims off a portion of the bag 150 after the open end has beensealed. The cutter assembly 482 can include a knife edge 486 thatextends to trim the bag 150 when the welding jaws 326, 350 are closed.Of course, other cutter assembly configurations can be used. Forexample, a welding jaw having a sealing wire that simultaneously sealsand cuts the bag 150 could also be used.

[0066] The welding assembly 74 also includes the pressure measurementdevices 324 mounted on the lower struts 318. The pressure measurementdevices are used to measure the pressure between the welding jaws 326,350 while the bag 150 is sealed. Recall that as the lower welding jaw326 reaches its uppermost vertical limit (i.e., the position where thewelding takes place), the lower struts 318 are substantially vertical.This orientation promotes accurate measuring of the welding pressurebecause the pressure measurement devices 324 are in axial alignment withthe forces exerted on the lower welding jaw 326 by the upper welding jaw350.

[0067]FIG. 12 illustrates an alternative arrangement for the pressuremeasuring device. In FIG. 12, a pressure measurement device 490 (i.e., aload cell or the like) is mounted in a recess in the upper welding jaw350. A contact disk 494 is mounted in a recess in the lower welding jaw326. Multiple sets of devices 490 and disks 494 can be spaced along thelength of the welding jaws 326, 350 as desired.

[0068] Regardless of the pressure measuring arrangement used, thepressure measuring devices 324, 490 are used to monitor the quality ofthe seal that is created by the welding jaws 326, 350, as will bedescribed below. Verifying the formation of a quality seal without humanintervention, and being able to document and record the process forfuture reference is an advantage of the bag filling station 50. The bags150 are sealed using heat to melt the open end of the bag 150 together,as is understood. At least three components are important to achieve agood seal: pressure, temperature, and time. The bag filling station 50monitors these three components so that the quality of the seal can bevalidated, which is especially important when packaging medical devices.

[0069] Time is the easiest to control, and refers to the time thepressure and heat are applied during the sealing process. Temperature ismore difficult to control and measure, but suitable products areavailable. Pressure is applied using the drive device 302, such as anelectric motor. Controlling the pressure entails controlling the currentin the electric motor. Alternatively, pressure could be controlled viaan air-cylinder (not shown). Pressure is measured using the pressuremeasurement devices 324, as described below.

[0070] During the sealing process, the weld wires 474 are heated to atemperature set by a controller or processor 502. The processor 502 ispreferably a programmable logic control device and can have a videodisplay 506. The temperature is held for a predetermined time dictatedby the processor 502. The actual temperature of the weld wires 474 ismonitored and temperature signals are sent to the processor 502 viasignal lines 510. The actual temperature is compared to predeterminedtemperature settings.

[0071] When the heat command is removed, the welding seam is allowed tocool and pressure is applied for a time specified by the processor 502.As seen in FIG. 8, the pressure measuring devices 324 are linked to theprocessor 502 via lines 512. The processor 502 analyzes the signals fromthe pressure measurement devices 324 and determines the actual weldingpressure applied. In one embodiment, the measured pressure, heat, andtime values are displayed on the video display 506 and are compared to apredetermined values to determine the quality of the seal. Additionally,two or more pressure measurements (corresponding to the number ofpressure measurement devices 324 or 490 used) are compared to oneanother to determine the consistency of the seal along the length of thewelding jaws 326, 350. With this approach, inconsistent or incompletesealing caused by debris between the welding jaws 326, 350 or wrinklesin the bag 150 can be detected.

[0072] The processor 502 reads and records the pressure and temperaturedata at a predetermined sampling rate that allows the process to bevalidated. Each seal has data associated with it that the seal washeated to a certain temperature and that a certain pressure wasmaintained for a certain time. If any of the data indicates thatimproper sealing conditions were present, the sealed bag is rejected.While not shown, the bag filling station 50 can also include a markingdevice that can be used to catalog the sealed bags by placing some formof indicating feature (i.e., a serial number, a bar code, or the like)on the bags that is linked to the weld data. When the bags are markedwith an indicating feature, the seal quality of any bag can be verifiedat a later time.

[0073] The operation of the bag filling station 50 will now bedescribed. The bags 150 are first stacked in the bag tray 262 so thatthe open ends are to the right as viewed in FIG. 3. The bag tray 262 isthen slid into place underneath the conveyor table 160. With theconveyor table 160 in the substantially horizontal first position P_(H),the lifting mechanism 278 is actuated to lift the stack of bags 150toward the bottom surface 210 of the body portion 162. As seen in FIG.4, when vacuum is applied to the lower cavity 186, the top bag 150 onthe stack of bags is engaged by the conveyor belt 178 due to the vacuumcommunication between the apertures 214 and the transverse apertures246. Once the top bag 150 is engaged with the conveyor belt 178, thelifting mechanism 278 is lowered to lower the stack of bags 150 awayfrom the bottom surface 210.

[0074] Next, the drive device 234 indexes the drive roller 166 such thatthe bag 150 moves with the conveyor belt 178 as shown in FIG. 5. Vacuumis applied to the follower roller 170 to hold the bag 150 in engagementwith the conveyor belt 178 as the bag 150 passes over the followerroller 170. At approximately the same time, the drive device 250 drivesthe linkage members 254 to move the conveyor table 160 from the firstposition P_(H) to the second, inclined position P_(I). As the bag 150approaches the top surface 202, vacuum is applied to the upper cavity182 to maintain the engagement between the conveyor belt 178 and the bag150. At about the same time, the vacuum is turned off in the lowercavity 186. Once the conveyor belt 178 has traveled a predetermineddistance (as gauged by the programmable motor or the sensing device),and the bag 150 is on top of the conveyor table 160, the drive device234 reverses direction to load the open end of the bag 150 into theloading station 58 as shown in FIG. 6.

[0075] FIGS. 13-20 and 21-28 illustrate (from the side and the front,respectively) the sequential operation of the bag manipulating assembly70 and the bag welding assembly 74 once the bag 150 is loaded into theloading station 58. As seen in FIGS. 13 and 21, the bag is moved intothe loading station 58 and the side edges of the bag 150 pass throughthe open grippers 430. The open end of the bag 150 is orientedsubstantially horizontally in the loading station 58 as shown. The upperand lower welding jaws 350, 326 (and therefore the upper and lower bagspreader assemblies 348, 352) are slightly opened to provide clearancefor the bag 150. In this position, the cam followers 426 are positionedin or near the dwell point 394.

[0076] Next, as seen in FIGS. 14 and 22, the grippers 430 close, therebysecurely clamping the opposing side edges of the bag 150 to maintaincontrol over the bag 150 at all times during the packaging operation.Additionally, the welding jaws 326, 350 close so that the suction cups334, 358 approach the open end of the bag 150 from both sides. Due tothe presence of the dwell points 394, the grippers 430 do not movetoward each other as the jaws 326, 350 close. Vacuum is applied to thesuction cups 334, 358 so that the suction cups 334, 358 engage bothsides of the open end of the bag 150.

[0077] As seen in FIGS. 15 and 23, the welding jaws 326, 350 then openslightly. Because the suction cups 334, 358 have a suction grip on thetop and bottom of the open end of the bag 150, the bag 150 opensslightly in response to the opening of the welding jaws 326, 350. Again,due to the dwell point 394, the grippers 430 do not move toward eachother. The grippers 430 (shown schematically in FIG. 15) remain closedto keep a secure grip on the side edges of the bag 150.

[0078] Next, as seen in FIGS. 16 and 24, the rotary actuators 338, 362are actuated so that the spreader plates 346, 370 rotate into the openend of the bag 150. The pins 342, 366 of the rotary actuators 338, 362also retract to draw the spreader plates 346, 370 closer to therespective suction cups 334, 358. Meanwhile, the suction is still beingapplied to the bag 150 by the suction cups 334, 358. The grippers 430remain closed.

[0079] At this point, it is worth noting that other spreader platearrangements can also be used to open the bag. FIGS. 30-32 illustratealternative upper and lower bag spreader assemblies 514 and 518,respectively. Instead of the rotary actuators 338, 362 having therotating and translating spreader plates 346, 370, the alternative upperand lower bag spreader assemblies 514 and 518 include respective upperand lower pivoting bag spreader plates 522 and 526. Respective actuators530 and 534 cause the pivoting bag spreader plates 522 and 526 to pivotinto and out of the open end of the bag 150 as is sequentially shown inFIGS. 31 and 32.

[0080] Returning to FIGS. 17 and 25, the welding jaws 326, 350 areopened wider so that the open end of the bag 150 is opened widely enoughto receive a package 102. Both the suction cups 334, 358 and thespreader plates 346, 370 aid in opening the bag 150. As best seen inFIG. 9, when the upper welding jaw 350 is moved upwardly to open the bag150, the gripper arms 418 pivot inwardly toward each other in responseto movement of the cam members 374. The inward pivoting of the gripperarms 418 moves the grippers 430 toward each other and facilitatesspreading the open end of the bag 150 apart. The grippers 430 remainclosed to hold the side edges of the bag 150.

[0081] Sometime before the package 102 is pushed into the bag 150, theconveyor table 160 of the bag loading assembly 66 is returned to thefirst, substantially horizontal position P_(H) (see FIGS. 1 and 4) sothat the package 102 can be pushed into the bag 150 without beingobstructed by the follower roller 170. Returning the conveyor table 160to the horizontal position also prepares the bag loading assembly 66 forpicking up the next bag 150 from the stack.

[0082] At this point, the bag 150 is ready to receive a package 102. Thepackage 102 is placed on the conveyor table 106 (see FIG. 1) and thedrive device 118 drives the conveyor belt 114 to move the package 102toward the loading station 58. The pusher arms 134 are in the retractedposition P_(R) (see FIG. 1a) to allow the package 102 to pass by. Whenthe sensor 142 detects the package 102, the conveyor belt 114 stops andthe pusher arms 134 move to the extended position P_(E) to overlie theconveyor table 106. The pusher arm assemblies 122 then move linearlytoward the waiting package 102 so that the pushing ends 138 engage thepackage 102 (see FIGS. 1b and 10) and push the package 102 into the bag150 (see FIGS. 18 and 26). The pusher arms 134 are then withdrawn fromthe bag 150 and returned to the retracted position P_(R) in anticipationof the next packaging cycle.

[0083] With the package 102 inside the bag 150, the bag 150 is sealed.As seen in FIGS. 19 and 27, the welding jaws 326, 350 close so that theopen end of the bag 150 closes. Just prior to closing, the spreaderplates 346, 370 rotate out of the bag 150. The suction is turned off atthe suction cups 334, 358. As the upper welding jaw 350 movesdownwardly, the gripper arms 418 pivot outwardly, away from each other.Since the grippers 430 are still closed on the side edges of the bag150, the outward movement of the gripper arms 418 acts to stretch thebag 150, thereby helping to flatten the open end of the bag 150 inpreparation for sealing.

[0084] To ensure that the open end of the bag 150 closes substantiallywithout any wrinkling caused by the bulky package 150 inside the bag,the linear actuators 434 connected to the gripper arms 418 (see FIGS. 8and 9) pull the gripper arms 418 even further outwardly, away from eachother. This additional outward movement of the grippers 430 stretchesthe side edges of the bag 150 apart even further to completely flattenthe open end of the bag 150 and to substantially remove any wrinklesthat could cause inconsistent or incomplete sealing.

[0085] Electricity is applied to the weld wires 474 to heat seal theopen end of the bag 150, as is understood. The processor 502 monitorsthe weld temperature, pressure, and time as described above to monitorthe quality of the seal obtained.

[0086] Either during, or just after welding, the cutter assembly 482 isactivated to trim the bag 150 as shown in FIG. 20. As shown in FIG. 28,the trimmed bag pieces 538 are removed from the loading station 58 usinga vacuum tube 542. The vacuum tube 542 is a tube positioned adjacent theloading station 58 where the trimmed bag pieces 538 are located. Vacuumsupplied to the vacuum tube 542 extracts the trimmed bag pieces 538 anddeposits them in a waste receptacle (not shown). Of course, othermethods of removing the trimmed bag pieces 538 can be used.Alternatively, the sealed bag 150 need not be trimmed at all.

[0087] With the bag 150 packed and sealed, the grippers 430 are openedto release the side edges of the bag 150 and the conveyor belt 178 isactivated to move the sealed bag 150 out of the loading station 58 andto the take-off conveyor 282 (see FIGS. 7 and 8). As seen in FIGS. 7 and8, the next packaging cycle is underway and the next bag 150 from thestack is concurrently being engaged and moved into the loading positionby the conveyor belt 178.

[0088] While not shown in the figures, the follower roller 170 can alsobe adapted to remove the air from inside the packed and sealed bag 150if vacuum packing is desired. Alternatively, vacuum packing could occurat a later time on a different machine.

[0089]FIG. 29 illustrates a packed and sealed bag 150. The sealed areaextends across the width of the bag 150 and is generally designated bythe reference numeral 546.

[0090] Various features of the invention are set forth in the followingclaims.

1. A device for filling and sealing bags, the device comprising: aframe; a loading station within the frame; a welding assembly coupled tothe frame and adjacent the loading station for sealing an open end of abag after a package has been loaded into the bag, the welding assemblyincluding an upper welding jaw and a lower welding jaw, wherein at leastone of the upper and the lower welding jaws is movably coupled to theframe via at least one support member; and a pressure measurement devicecoupled to the welding assembly for measuring the pressure between theupper and the lower welding jaws when the bag is being sealed.
 2. Thedevice of claim 1, wherein the pressure measurement device is mounted onthe at least one support member.
 3. The device of claim 1, wherein thepressure measurement device is a load cell.
 4. The device of claim 1,further including a processor that processes a signal sent from thepressure measurement device to analyze the quality of the seal.
 5. Thedevice of claim 1, wherein the lower welding jaw is movably coupled tothe frame via two support members that are capable of moving the lowerjaw into welding engagement with the upper welding jaw, and wherein apressure measurement device is mounted on each of the support members.6. The device of claim 5, further including a processor that processessignals sent from each of the pressure measurement devices to analyzethe quality of the seal.
 7. The device of claim 1, wherein the pressuremeasurement device is mounted in a recess in one of the upper and thelower welding jaws.
 8. The device of claim 1, further including atemperature sensor coupled to the welding assembly for measuring thetemperature during sealing.
 9. The device of claim 1, further includinga timer coupled to the welding assembly for determining the length oftime in which the welding jaws seal the bag.
 10. A device for fillingand sealing bags, the device comprising: a frame; a loading stationwithin the frame; a package loading assembly coupled to the frame andadjacent the loading station; a bag loading assembly coupled to theframe and adjacent the loading station, the bag loading assembly beingoperable to load an open end of a bag into the loading station; a bagmanipulating assembly coupled to the frame to facilitate opening thebag; a welding assembly coupled to the frame for sealing the open end ofthe bag, the welding assembly including upper and lower welding jaws;and a pressure measurement device coupled to the welding assembly formeasuring the pressure between the upper and lower welding jaws when thebag is being sealed.
 11. The device of claim 10, further including atemperature sensor coupled to the welding assembly for measuring thetemperature during sealing.
 12. The device of claim 10, furtherincluding a timer coupled to the welding assembly for determining thelength of time in which the welding jaws seal the bag.
 13. A method ofpackaging an item in a bag using an automated packaging device, themethod comprising: loading an open end of a bag into a loading station;loading the item into the bag; providing a welding assembly having anupper welding jaw and a lower welding jaw, at least one of the upper andthe lower welding jaws being movably coupled to the frame via at leastone support member, and a pressure measurement device mounted on the atleast one support member for measuring the pressure between the upperand the lower welding jaws when the bag is being sealed; sealing theopen end of the bag between the welding jaws after the item has beenloaded into the bag; measuring a sealing pressure with the pressuremeasurement device; and sending a pressure signal to a processor todetermine conditions under which the seal was created.
 14. The method ofclaim 13, wherein the lower welding jaw is movably coupled to the framevia two support members that are capable of moving the lower welding jawinto welding engagement with the upper welding jaw, wherein a pressuremeasurement device is mounted on each of the support members, andwherein a pressure signal from each of the pressure measurement devicesis sent to the processor to determine conditions under which the sealwas created.
 15. The method of claim 14, wherein the support members areoriented substantially vertically during sealing.
 16. The method ofclaim 13, further including measuring a sealing temperature with atemperature sensor.
 17. The method of claim 13, further includingproviding a predetermined sealing time in which the bag is sealed.
 18. Awelding assembly for a bag filling device, the welding assemblycomprising: an upper jaw movable in a substantially vertical plane; alower jaw movable in the same substantially vertical plane as the upperjaw and supported on the frame via two support members; a pressuresensor coupled to the jaws for measuring a welding pressure between thejaws; and a processor coupled to the pressure sensor to receive a signalfrom the pressure sensor and to determine conditions under which theweld was created.
 19. The welding assembly of claim 18, wherein thepressure sensor is mounted on one of the support members.
 20. Thewelding assembly of claim 18, wherein the pressure sensor is mounted ina recess in one of the upper and the lower jaws.
 21. A method of sealinga bag, the method comprising: positioning a bag between upper and lowerjaws; moving the jaws together in a substantially vertical plane to sealthe bag; sensing a pressure between the jaws when the jaws are together;sending pressure measurements to a processor; and determining thequality of the seal by analyzing whether the pressure measurements fallwithin a predetermined set of allowable limits.
 22. The method of claim21, wherein sensing the pressure between the jaws includes positioning apressure sensor on a support member coupled to one of the upper and thelower jaws.
 23. The method of claim 22, wherein the support member issubstantially vertical when the jaws are together.
 24. The method ofclaim 21, wherein sensing the pressure between the jaws includespositioning a pressure sensor in a recess in one of the upper and thelower jaws.
 25. The method of claim 21, further comprising: sensing atemperature between the jaws when the jaws are together; sendingtemperature measurements to the processor; and determining the qualityof the seal by analyzing whether the temperature measurements fallwithin a predetermined set of allowable limits.